Llywelyn the Great

Llywelyn the Great (1172-11 April 1240) was Prince of Gwynedd from 1195 to 1240 (succeeding Dafydd ab Owain Gwynedd and preceding Dafydd ap Llywelyn) and Prince of Powys Wenwynwyn from 1216 to 1240 (succeeding Gwenwynwyn ap Owain and preceding Gruffydd ap Gwenwynwyn).

Biography
Llywelyn ap Iorwerth was born in Dolwyddelan, Wales in 1172, the son of Iorwerth ap Owain and the grandson of Owain Gwynedd. By the 1180s, he had already taken up arms against his uncles Dafydd ab Owain Gwynedd and Rhodri ab Owain Gwynedd and he ruled the territories taken from Dafydd east of the Conwy, while his cousins Gruffudd ap Cynan and Maredudd ap Cynan took over Rhodri's lands. Llywelyn backed Gwenwynwyn ap Owain in his struggles against England, but he used his defeat to become prince of all North Wales, and he became master of Gwynedd.

Llywelyn, nicknamed "the Great", expanded the boundaries of Gwynedd and married King John of England's daughter Joan in 1205 in an attempt to ally with England against his rivals. In 1208, after John captured Gwenwynwyn and stripped him of his lands, Llywelyn annexed southern Powys and northern Ceredigion. In 1209, he accompanied John in a campaign against King William I of Scotland. However, Llywelyn's alliance with William de Braose, 4th Lord of Bramber led to a deterioration in Anglo-Welsh relations, and, by 1218, he drove the English from South Wales, seizing Cardigan and Carmarthen during the First Barons' War. The 1218 Treaty of Worcester allowed for Llywelyn to retain his conquests, and he recovered Cardigan, Carmarthen, and Montgomery during the early 1230s after the English recaptured these castles in 1223. Wales was at peace until Llywelyn's death in 1240.